It is fair to say that the Serene Danang is "on the beach", but if you are expecting a Thailand-esque beach trip, I'm afraid to say that this won't be found here.
The area around the hotel is undergoing intense construction and development. In 5-10 years, it may be an excellent experience, but the surroundings make for an extremely unpleasant stay. There are a handful of restaurants within a 20-30 minute walking distance and none of these are particularly attractive. In the end, we ate in the least-worst looking one. Construction has left the area untidy and unattractive, though I wouldn't say that it is dirty per se.
The Serene front desk staff are pleasant, though don't communicate very well in English. The hotel told us they would keep our passports in lieu of a deposit. When we said we would rather put a charge on our credit cards (as is more common?), they said their credit card machine was broken. However, upon reading other reviews, it seems that the passport method is standard practice at the hotel.
The room is clean enough, with all the basics expected of a 4-star hotel, but the experience is just that - basic. There is a gym in the hotel and a swimming pool; the pool is tiny and overlooks construction, the gym just a small dark room with a multi-station and a couple treadmills.
Decent if you are just passing through, but otherwise better to spend more to stay in the city or at a resort.